Condenser and clamp therefor



June 23, 1925. 1,543,326

w. DUBILIER CONDENSER AND CLA M? THEREFOR Filed Feb. 7, 1921 PatentedJune 23, 1925.

UNITED STATES 1,543,326 PATENT OFFICE.

WILLIAM DUBILIER, OF NEW YORK, N. Y., ASSIGNOR TO DUBILIER CONDENSER &RADIO CORPORATION, A CORPORATION OF DELAWARE.

commnsnn Am) CLAMP THEREFQR.

Application filed February 7, 1921. Serial No. 442,945. I

To (all whom it may concern:

Be it known that I, WILLIAM DUBILIER, a citizen of the United States,residing-at New York, in the county of New York and State of New York,have invented a certain newand useful Condenser and Clam Therefor,ofwhich the following is a speci cation.

The invention has for an object to provide a condenser having a clampwhich, while affording the necessary degree of pressure upon thecondenser stack, will yet involve 'but a small number of parts of simplecon.-

struction, light weight and small size, and which may be readilyassembled, thus mak ing the condenser particularly adapted for use wheresmall units are desired. It is to be understood, however, that-the'invention is not limited in utility to condensers of small size.

Another object of the invention is to form a condenser clamp which willnot tend to bow or warp over the active area of the condenser when thecompression is applied to the latter, or in use of the condenser,-

for example, when expansion or contraction occurs due to temperaturechanges.

Another object of the invention is to provide a clamping device forcondensers which may be adjusted to exert the necessary pressure uponthe stack merely b pressing or forcing certain parts of sai device intooperative position.

Further objects and advantages of the invention will be in part obviousand in part specifically mentioned in the description hereinaftercontained, which, taken in connection with the accompanying drawings,discloses a preferred embodiment of the 1nvention; such embodiment,however, is to be considered merely as illustrative of its princi le.

In t e drawings- Figure 1 is a perspective view of a condenser and clampmade according to the invention;

Fig. 2 is a plan view of the structure shown in Fig. 1, certain of theparts being cut away;

Fig. 3 is a side view of one of the compresslon-appiying members showndetached. The invention is disclosed in connection with a condenserstack consisting generally of the dielectric sheets 1,-for example, ofmica,-isterleaved with suitable groups of conducting sheets 2 and-3,respectively, the

dielectric sheets overlapping the conducting sheets on three sides, buteach group of conducting'sheets projecting beyond'the stack (in thefourth side to form terminals 4 and 5. The condenser stack is preferablyimpregnated and then subjected to high pressure in the process ofmanufacture in such mancondensers of very small size which, however,should still be of as high efliciency as possible and. substantiallyconstant in capaclty.

In order to obtain the desired efficiency, it is advantageous to placethe elements of the condenser under suflicient pressure to insure thatthe intimate contact between the dielectric and conducting sheetseffected as above described, will be maintained during use, but thisinvolves some difiiculties if the volume of. the condenser is to berestricted to narrow limits. For example, if clamping plates be employedin op osite faces of the condenser stack and a su cient compressionobtained by bolts or the like connecting said plates, it is necessary tohave the plates overlap the stack sufficiently to accommodate the bolts,and to make the plates so strong and heavy that they will not how enoughto unduly release the pressure on the central portion of the stack whenthe bolts are tightened up. Both of the above considerations tend to aconstruction of clamp which would be heavy and take up an undue amountof space, and the operations of assembling the condenser and placing itunder proper compression, require special appliances and care- -iulwork. Furthermore, if the condenser stack heats up in use, the expansionof the stack will also tend to how the clamping plates sa as release thepressure on the losses to be therein.

To facilitate the operations of assembling the condenser and placing thestack under the desired pressure, it is preferred to construct thecondenser clamp of parts which will apply the necessary pressure merelyby pressing or forcing them into proper position relative to each other.As shown, bearing plates 6 are employed on the opposite faces of thestack, such bearing plates having flat surfaces engaging the stack andbeing sufiiciently strong and rigid to distribute pressure over the areaof the stack. In the present instance, the bearing members are made ofmetal, which is probably best suited to fulfill the requirements.

The compression is applied to the stack by means of members or clamps 7,each arched to extend around a side 0 the stack, and having opposed endportions 8 adapted to engage the outer surfaces of the bearing members 6and pressing upon the same with sulficient force to maintain the laminaeof the condenser in proper relation to each other. If desired, engagingparts may be provided between the members 6 and 7,' such as grooves 9,in the bearing members engaging the end portions 8 of thecompression-applying members 7 ,to prevent accidental displacement ofthe latter.

If the clamp be employed in connection with condenser stacks which havepreviously been subjected to a high pressure, it is only necessary thatthe clamp bear on the stack firmly enough to insure that the elements ofthe condenser will not shift in use. However, if the condenser stack hassome irregularities,such as small particles of wax on its surfaces,thepressure of the clamp will be sufiicient to take out such irregularitieswhen the condenser becomes warm and hold the elements in proper shapethereafter.

The compression-applying members 7 are made of stiffmaterial,ordinarily, metal, and are forced over the bearing members 6with what might be termed a drive or force fit. Thus the forcing ofmembers 7 over the bearing members places the condenser stack under thenecessary pressure without necessitating the use of a press, or thetightening of bolts, to obtain thenecessary compression. In the presentinstance, the end portions8 of the members 7 are provided with inclinedsurfaces, edges or cutaway corners 10 so that the members may be readilydriven into proper position by means of a hammer or the like.

As the clamp, in the particular form of the invention chosen forillustration, is independent of the circuit connections of thecondenser, I have shown insulating sheets 11, for eXample ,of mica,interposed between both bearing members 6 and the stack to prevent shortcircuiting.

It is preferred to construct the bearing members and thecompression-applying members 7 in such manner that compression isapplied to the stack at points which are within the confines of thelatter, so to speak. Thus the bearing members will not oe subjected tostresses which would tend to bow them,'either when the compression isapplied or if the stack tends to expand in heating during use, since thepressure of the members 7 will be applied directly against the fiat faceof the condenser stack. Furthermore, the application of pressure may berestricted to the confines of the active area of the condenser,that is,the overlapping portions of the conducting sheets i and 5,-- if it isfound that the overlapping edges of the dielectric sheets, which arespaced apart a distance equal to the thickness of the conducting sheets,tend to give sufiiciently to bow the bearing members should compressionbe applied to points even with the overlapping edges of such sheets. Ifthe compression be applied to the bearing members at points materiallyoutside of the confines of the stack, the edges of the stack tend to actas fulcruins, with the result that the central portions of the bearingmembers are bowed outwardly so as to release the compression on theactive area of the condenser, and the same tendency occurs when theheating of the condenser stack expands it.

The members 7 are preferably made of a metal,such as steel,-which issufficiently springy to be spread or forced apart at the opposed endportions 8 of the members when they are adjusted to operative position,and sufficiently strong and stiff to give the necessary com ression.Thus, if the stack should expand due to heating in use, this expansionmay be taken up by the members 7 without detriment. Ordinarily, theyielding of the clamping members of a condenser has a tendency torelease the compression on one part or another of the active area of thestack, but with a construction of the above character, the bearinsurfaces of members 5 and 6 will still be maintained parallel afterexpansion, and the members 7 will still exert the proper'amount of uniform compression upon them.

Since the bearing members need not be subjected to bending stresses, itis not necessary to make them of heavy weight, nor need they be extendedto overlap the stack. The compression-applying members 7 are also ofrelatively li ht weight, and need be spaced from the si es of the stackonly a sufficient distance to provide clearance, with the result thatthe clamp as a whole is comparatively light and occupies but a smallamount of space.

'While a specific embodiment of the invention has been described, itwill be obvious that many of the features of the invention areindependently useful, and that many changes may be made without departinfrom the spirit of the invention as define in the following claim.

I claim:

'An electrical condenser comprising a stack of conducting and dielectricsheets, bearing members engaging the op osite faces of said stack, eachof said mem ers having openended grooves in its outer face along itsopposite edges, and clamps fonholdin said members and said stacktogether, said 0 amps having opposed edges and being disposed atopposite sides of the condenser, the edges of each clam engaging theooves in the bearing members at each si e of the condenser, each clamphavin cutaway corners at the ends of its opposed edges, to enable it tobe forced upon the condenser in'gripping position.

In testimony that I claim the foregoing, I have hereunto set my handthis 4th day of January, 1921.

- WILLIAM DUBI-LIER;

